1. Field of the Invention
The present invention relates to image processing apparatuses, and in particular, to processing of encoded image data.
2. Description of the Related Art
Apparatuses having the following functions are disclosed: encoding moving image data in an encoding format, such as, the Moving Picture Experts Group (MPEG) format, recording encoded image data on recording media, such as optical disks, and playing it back.
In some cases, image data encoded in this way is read from recording media and transmitted through digital transmission lines, such as the Institute of Electrical and Electronic Engineers 1394 (IEEE1394) interface.
For transmitting image data read in this way, a technique is disclosed (for example, in Japanese Patent Laid-Open No. 11-220694), in which when a request for playing back a still image is submitted, still image data generated with skipped macroblocks having no prediction error with respect to a reference image is inserted into moving image data and transmitted.
In the related art described above, still image data having no difference with respect to a reference frame is inserted and transmitted. In general television systems, such as the National Television System Committee (NTSC) system, an image of one frame is interlaced with images of two fields. When a reference image frame inserted as a still image has an object of shooting that sharply moves during the interval between two fields, a decoded image is disadvantageously blurred.